Technical Field
The present disclosure relates to a method of assembling a front side end to a sub-frame of a vehicle. More particularly, the present disclosure relates to a method of assembling a front side end to a sub-frame of a vehicle by increasing a combined area between a mounting nut of a sub-frame and a side member to realize a firm supporting structure.
Background
In general, a front sub-frame, hereinafter, referred to as a sub-frame, of a vehicle mounts power train parts such as an engine and a transmission in a monocoque vehicle body structure.
FIG. 1 is a perspective view illustrating assembly between a conventional side member and a sub-frame.
Referring to FIG. 1, a sub-frame 101 is combined with a lower part of a front side member 103, hereinafter, referred to as a side member, on both sides of a vehicle body 100 through a mounting nut and a mounting bolt.
FIG. 2 is a perspective view of an assembly unit in a conventional method of assembling a side member with a sub-frame. FIG. 3 is a cross-sectional view of an assembly unit in a conventional method of assembling a side member with a sub-frame.
Referring to FIGS. 2 and 3, a mounting nut 110 for engaging the sub-frame 101 with the side member 103 is first assembled with a bracket 120 and is inserted through a through hole H formed in a lower surface of the side member 103 to be assembled.
The mounting nut 110 is assembled with the bracket 120 and the side member 103 by arc welding and is combined with the bracket 120 and the side member 103 by spot welding.
A degree of freedom of motion of the mounting nut 110 must be suppressed in order to be firmly combined with the sub-frame 101. The mounting nut 110 has a supporting structure in which a circular supporting end 111 and the bracket 120 are combined with the mounting nut 110 in the center of the mounting nut 110 and the head 113 of the mounting nut 110 and a periphery of the through hole H of the side member 103 are combined with each other so that the degree of freedom of motion of the mounting nut 110 is suppressed.
Finally, the degree of freedom of motion of the mounting unit 110 is suppressed by stiffness of the bracket 120 and the side member 103 combined with the mounting nut 110.
However, in the conventional art, the mounting nut 110 and the bracket 120 are assembled with the side member 103 by a point combination or a line combination so that there are limitations on increasing combination stiffness or input point stiffness.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure.